Diffuser



Jan. 27, 1942. F. L. SLADE 2,270,901

DIFFUSER Filed April 27, 1958 s Sheets-Sheet 1 flir' diffuses abaui' Alma 50 z of air f Zows 3fce'z' from opening. back ikropzg'k genter of cqne nzlrmg wzikfresh wiih a'spLraZ flow fomzng' a conical shape.

CyZiIzder InZei connecied i0 source of supply.

INVENTOR.

Franklin .[hSZCZdG- ATTORNEY I l I l I I I Closed boiiom DIFFUSER Filed April 27, 1938 3 Sheets-Sheet 5 4--- lA/LET.

OUTLET OPEN/N6 5 I OUTLET MKM 11V VEl V TOR.

Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE 3 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to devices for diiiusing air, vapor and gases discharged from a duct for the'purpose of reducing the velocity of flow and the attending noise and diverting the directional characteristics of the flow in such a manner as to minimize the draft caused thereby.

An object of the invention is to provide a simple, inexpensive and highly efiicient device which is equally applicable in principle for use as an air diffusing device in a ventilating system in vessels, vehicles and rooms for eliminating undesired air drafts and for use as a muflier for gas discharge under high velocity from such conduits as an exhaust pipe of an internal combustion engine, so as to reduce the attending noise without resulting prejudicial back pressure.

To these and other ends, it is proposed to provide a cylindrical member with one or both ends open, as desired.

The inlet to the cylinder comprises a pipe set tangentially to the perimeter of the cylinder, and this pipe is suitable for attachment to the conduit conveying the high velocity fluid from its source, whether the fluid be air for ventilating purposes or discharge gas from an internal combustion engine. By this construction the fiuid entering the cylinder under pressure is caused to flow spirally toward and out through the end of the cylinder forming a cone of spiral air flow. At a certain distance past the open end of the cylinder, predetermined by the dimensions of the device, a substantial part of the flow, by reason of aspiration, falls in toward the center of the cone and back toward the cylinder, enhancing the mixing of fresh air with ambient or surrounding air. The result is a minimization of noise and draft which would otherwise attend an undiverted air or gas flow. Suitable means may also be employed for regulating the inlet opening into the cylinder and the dimensions of the device may be modified to suit the prescribed conditions.

With the foregoing and other objects in view, the invention resides in the combination of arts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Fig. l is a diagrammatical showing of the simplest form of the invention with a cylinder with one open end, an inlet extending from a source of fluid in flow, and a graphic showing of the air flow resulting after discharge from the cylinder.

Fig. 2 is a view in side elevation of one form of the device including an outer stationary cylinder with an integral tangential inlet, a closed bottom cylinder rotatably adjustable therein and with a port which may be put in and out of registry with the inlet.

Fig. 3 is a view in top plan of the device shown in Fig. 2.

Fig. 4 is a diagrammatical view in elevation of a device similar to that shown in Fig. 2 with both ends of the cylinder open for gas discharge.

Fig. 5 is a diagrammatical view similar to Fig. 2 with the outlet rim of the cylinder inclined downwardly.

Fig. 6 is a diagrammatical view similar to Fig. 5 with both ends of the cylinder open and the rims inclined.

Fig. 7 is a diagrammatical view in elevation of a device similar to Fig. 2 with a modified inlet.

Fig. 8 is a view in top plan of the device shown in Fig. '7.

Fig. 9 is a diagrammatical View of a modification with a cylinder with closed ends, a tangential inlet of the type shown in Figs. 7 and 8 and a tangential outlet.

Fig. 10 is a top plan view of that shown in Fig. 9.

Referring more particularly to the drawings, and to that type of device shown in Figs. 2 and 3, the device comprises a stationary cylinder I which is open at both ends, inside of which is loosely fitted an inner cylinder 2. The outer cylinder l is provided with a circumferential slot 3 which receives the shank of a screw wing bolt 4 forming the means for rotatable connection of the two cylinders.

Integral with the outer cylinder l is a pipe 5 which is disposed tangential to the perimeter of the outer cylinder. The inner cylinder 2 is provided with a cut out portion 6 which is adapted to align with the tangential inlet to the outer cylinder, as shown in Fig. 2, or be partially aligned or wholly out of alignment so as to regulate the fiow of air from the source to the inside of the inner cylinder 2. As a convenient means fo turning the inner cylinder 2 within the outer cylinder i, there is provided a projection I for manual engagement in order to valve the device as'conditions prescribe. The turning of the wing bolt 4 affords a means for clamping the cylinders against rotation and a locking of the same in the desired adjusted position.

Now, by referring to Fig. 1, which is a diagrammatical showing of the structure shown in Figs. 2 and 3, the air or gas flowing, from some suitable source, into the interior of the cylinder, flows out the upper end 8 of the cylinder. The inlet, being tangential to the perimeter of the cylinder, causes a spiral upward flow. This flow exterior of the upper rim of the cylinder partakes of the nature shown in Fig. 1. In other words, the flow is not only spirally upward, but also in the form of a cone defined by lines of approximately 30 degrees to the axis of the cylinder. The particular illustration is one under actual tested and proven conditions which included an inner cylinder of approximately 4%; inches diameter and inches length; an inlet of 4 inches height and 1 inches width, and an initial air velocity of 1200 feet per minute. Under these conditions, and as indicated in Fig. 1, at approximately a distance of three feet from the upper rim of the cylinder, approximately 30 per cent of the air, by reason of aspiration, flowed back through the center of the cone, the direction of air flow being indicated by arrows, and the flow thus mixed with the fresh air. The resulting effect is definitely to minimize the noise of air or gas flow and to diffuse the same to minimize draft which would occur in direct uninterrupted flow. This enhances the mixing of the fresh air with the ambient or surrounding air. It has been found that this same phenomenon is most pronounced and is most effective, when the length of the discharge cylinder of the diffuser is maintained between one and two times the diameter thereof.

With further reference to Fig. 2 it will be seen that the means for mounting the inner member 3 rotatably within the cylinder I comprises merely the Wing bolt 4 and slot 3. This makes it possible to reverse the inner member 8 with respect to the cylinder I from the position shown for directing the air upwardly to a position for directing the air downwardly when desired. The advantage of this feature is that when the device is to be used as a ventilator, using warm air, the device is adjusted so as to direct the air downwardly and the reverse adjustment is made when using cool air, in which case the cool air is directed upwardly. The device may be installed at any desired angle by proper inlet connections to the main. A further advantage of the simplified construction is that the inner member 8 is readily removable for cleaning purposes.

Fig. 4 merely shows a possible modification providing for an outlet at both ends of the cylinder, in which case the same phenomenon of air flow out through the upper and lower ends 8 and 9 would occur as shown and described in connection with Fig. I. This type of device may also be disposed horizontally or at any desired angle.

The modifications shown in Figs. 5 and 6 provide for varying and controlling the direction of the conical flow by reason of the inclined rim ID on the upper end of the cylinder in Fig. 5 and the upper and lower ends Ill and II in Fig. 6.

Figs. 7 and 8 show another modification of inlet to the cylinder, particularly suitable for use in connection with the cylinder for muffling the exhaust gases of internal combustion engines, the cylinder being closed at one end and open at the other.

Figs. 9 and 10 are merely a variation of Figs.

'7 and 8, in which former the cylinder is closed at both ends and the inlet and outlet into and out of the cylinder is through pipes arranged tangentially to the perimeter of the cylinder.

I claim:

1. In a device for diffusing the flow of fluid, a pair of relatively rotatable cylinders, one within the other, and with a common open discharge outlet end, one of said cylinders carrying an inlet duct arranged tangentially with respect to the perimeter of said cylinder, and the other cylinder being provided with a port adapted to be placed into and out of registry with said inlet duct, said inlet duct being connected with a source of fluid, means causing a flow of fluid from said source to said duct, said cylinders being relatively large in cross sectional area with respect to, the cross-sectional area of said inlet duct, thereby constituting in effect an expanding taper to the diffusion system in order to decrease the velocity from said inlet to said outlet end, said inner cylinder being of a length equal to from one to two times its diameter, all whereby the flow of fluid from the outlet of said cylindrical member is of a spirally conical form for a predetermined distance from said outlet and further whereby a substantial portion of said fluid flow is automatically diverted inwardly so as to be returned toward the center of the cone and toward said outlet.

2. In a ventilation system, an outlet structure for distributing fluid with the substantial elim ination of noise and draft, said structure comprising an unobstructed inlet conduit, a cylindrical member having a free and unobstructed open end comprising the discharge orifice of the structure, said discharge orifice being of the same diameter and outline as the cylindrical member itself, said inlet conduit being disposed tangentially with respect to the perimeter of said cylindrical member, and communicating therewith, said cylindrical member being of a length equal to from about one to two times its diameter, all whereby the fluid is caused to swirl within said cylindrical member and to flow from said discharge orifice in a spirally conical form for a predetermined distance, and a'portion of said flow being automatically diverted inwardly toward the center of the cone and back toward said discharge orifice.

3. In a ventilation system, an outlet structure for distributing fluid with the substantial elimination of noise and draft, said structure comprising an inlet conduit of constant cross-section throughout its length, a cylindrical member having a free and unobstructed open end comprising the discharge orifice of the structure, said inlet conduit being disposed tangentially with respect to the perimeter of said cylindrical member, and communicating therewith, said cylindrical member being of a length equal to from about one to two times its diameter, all whereby the fluid is caused to swirl within said cylindrical member and to flow from said discharge orifice in a spirally conical form for a predetermined distance, and a portion of said flow being automatically diverted inwardly toward the center of the cone and back toward said discharge orifice, the rim of the discharge end of the cylindrical member being disposed in an inclined plane, whereby the direction of flow of the cone is diverted from the perpendicular.

FRANKLIN L. SLADE. 

